Large VLDL Concentrations Research Articles

Compared to Regular Lutein, a Lutein Nano‐Emulsion Yields a More Atherogenic Lipoprotein Profile Associated with Higher Concentrations of Cholesterol in Adipose Tissue in Guinea Pigs

We challenged 24 guinea pigs (8/group) with a high cholesterol diet (0.25g/100g) alone (control group) or in combination with 3 mg/d of Regular lutein (R‐lutein) or 3 mg/d of lutein prepared in nano‐emulsion (NANO) (average particle diameter = 250 nm). After 6 weeks, guinea pigs were sacrificed and blood was collected to measure plasma lipids and lipoprotein size and number by Nuclear Magnetic Resonance and adipose was harvested to determine concentrations of both free and esterified cholesterol. Contrary to what we expected, guinea pigs from the NANO group had the greatest concentrations of plasma cholesterol (P<0.001). In addition, the NANO group had higher concentrations of large VLDL and total LDL particles (p<0.0001). Moreover, cholesterol concentration in the adipose tissue was highest in the NANO group (11.5 ± 2.5 mg/g), intermediate in the control group (10.2 ± 1.5 mg/g) and lowest in the R‐lutein group (9.2 ± 0.8 mg/g) (p< 0.01). In contrast hepatic cholesterol concentrations were highest in the NANO compared to the R‐lutein and control groups (P < 0.01). Further, we found a positive correlation between plasma cholesterol and free cholesterol in the adipose (r = 0.493, p = 0.014) and with large VLDL (r = 0.700, P < 0.001). These data suggest that guinea pigs fed the NANO emulsion have lower concentrations of cholesterol in the liver because they are secreting cholesterol in the large VLDL particles and possibly both lipoproteins VLDL and LDL are depositing the excess cholesterol in extra‐hepatic tissues (adipose), possibly via scavenger receptors

Intrahepatic Fat Accumulation and Alterations in Lipoprotein Composition in Obese Adolescents

Among other metabolic consequences, a dyslipidemic profile often accompanies childhood obesity. In adults, type 2 diabetes and hepatic steatosis have been shown to alter lipoprotein subclass distribution and size; however, these alterations have not yet been shown in children or adolescents. Therefore, our objective was to determine the effect of hepatic steatosis on lipoprotein concentration and size in obese adolescents. Using fast magnetic resonance imaging, we measured intrahepatic fat content in 49 obese adolescents with normal glucose tolerance. The presence or absence of hepatic steatosis was determined by a threshold value for hepatic fat fraction (HFF) of 5.5%; therefore, the cohort was divided into two groups (HFF > or <5.5%). Fasting lipoprotein subclasses were determined using nuclear magnetic resonance spectroscopy. Overall, the high-HFF group had 88% higher concentrations of large VLDL compared with the low-HFF group (P < 0.001). Likewise, the high-HFF group had significantly higher concentrations of small dense LDL (P < 0.007); however, the low-HFF group had significantly higher concentrations of large HDL (P < 0.001). Stepwise multiple regression analysis revealed that high HFF was the strongest single correlate, accounting for 32.6% of the variance in large VLDL concentrations (P < 0.002). The presence of fatty liver was associated with a pronounced dyslipidemic profile characterized by large VLDL, small dense LDL, and decreased large HDL concentrations. This proatherogenic phenotype was strongly related to the intrahepatic lipid content.

Differences in the relation of obesity to serum triacylglycerol and VLDL subclass concentrations between black and white children: the Bogalusa Heart Study

Obese children and adults, particularly those with abdominal obesity, have an elevated serum triacylglycerol concentration. Furthermore, triacylglycerol concentrations are generally higher in whites than in blacks, and the relation of obesity to triacylglycerol concentrations may be stronger in whites. However, there is little information on the relation of obesity to the metabolically distinct subclasses of VLDL in children. The objective was to examine possible differences between blacks (n = 367) and whites (n = 549) in mean concentrations of triacylglycerols, in mean concentrations of small and large VLDL, and in the relation of waist circumference to concentrations of triacylglycerol and VLDL subclasses. We measured VLDL subclass concentrations and assessed the relation of various obesity indexes to triacylglycerols in a cross-sectional study of 10- to 17-y-olds. The mean triacylglycerol concentration was 0.3 mmol/L (25 mg/dL) higher in white than in black children, primarily because of a 0.2-mmol/L (140%) difference in mean concentrations of large VLDL. In contrast, the mean concentrations of small VLDL differed by only 0.05 mmol/L (29%). In addition, the relations of waist girth to concentrations of triacylglycerol and large VLDL were 2- to 6-fold stronger among white children than among black children. Although white children had higher concentrations of large VLDL than did black children, this difference increased from 0.1 to 0.4 mmol/L across quintiles of waist circumference. Waist circumference was not significantly related to concentrations of small VLDL. These contrasting associations with obesity, which differ between white and black children, suggest that information on VLDL subclasses could provide additional information on the risk of obesity-related ischemic heart disease.

Changes of lipoprotein profile in familial dysbetalipoproteinemia with gemfibrozil

purpose: This prospective study was undertaken to evaluate the effects of gemfibrozil on the lipoprotein profile of patients with familial dysbetalipoproteinemia (type III hyperlipoproteinemia). patients and methods: Eight patients with well-defined familial dysbetalipoproteinemia associated with the apolipoprotein (apo) E2/2 phenotype were treated with gemfibrozil (Lopid) at a dose of 600 mg twice daily for a period of 10 months. Blood samples were taken at baseline, after 4 and 5 weeks, after 3 months, and after 10 months. The separation of serum lipoprotein (sub)fractions was performed by a recently developed density gradient ultracentrifugation technique. results: After 4 weeks of gemfibrozil therapy, the concentrations of serum total cholesterol and serum total triglyceride had decreased by 45% (from 11.87 to 6.51 mmol/L, p < 0.01) and by 63% (from 6.08 to 2.23 mmol/L, p < 0.001), respectively. The cholesterol concentrations of very-low-density lipoprotein-1 (VLDL 1) (large VLDL), VLDL 2 (small VLDL), and intermediate-density lipoprotein (IDL) had decreased significantly by 73%, 74%, and 34%, respectively. The low-density lipoprotein (LDL)-cholesterol level remained unchanged, whereas the particle size of LDL showed a small but significant increase (from 24.09 nm to 24.43 nm, p < 0.01). The concentrations of high-density lipoprotein (HDL)-cholesterol, apo A-I, and apo A-II had increased significantly by 23%, 13%, and 29%, respectively. Only minor changes in the composition of the lipoprotein (sub) fractions were observed. After 3 months of treatment with gemfibrozil, the concentrations of serum total cholesterol and serum total triglyceride were 5.95 mmol/L and 2.06 mmol/L, respectively, and after 10 months of treatment with gemfibrozil, the concentrations of serum total cholesterol and serum total triglyceride were 6.19 mmol/L and 2.27 mmol/L, respectively. conclusion: Gemfibrozil treatment in patients with familial dysbetalipoproteinemia resulted in a marked reduction of the concentrations of large VLDL, small VLDL, and IDL, and an increase in the levels of HDL, apo A-I, and apo A-II. These changes are considered to exert an antiatherosclerotic effect in these patients.